Southwick, Stephen :

Glozer Dr, Kitren

Ingels, Chuck

Hansen, Randy :

Effects of Messenger on â?? Bartlett â?? Pear Fruit Size and Cropping in 2003 Stephen Southwick Kitren Glozer Randy Hansen Zaheer Khan Introduction Improved fruit size and cropping of â?? Bartlett â?? pear in California would provide better returns to growers in a market that shows increasing demand for fresh pears , as opposed to canning pears . Growers are interested in maximizing production and fruit size since they are paid more for high yields and large size fruits . Chemicals that are safe for the environment , while providing an economic gain are of interest to pear growers . Messenger is a chemical with plant growth regulating activities which may improve cropping and fruit size in European pears , specifically â?? Bartlett â?? , the major cultivar grown in California . Methodology Applications of Messenger were made in a commercial orchard near Courtland ( Yolo County ) . Trees were â?? Bartlett â?? on â?? Winter Nelis â?? ( both Pyrus communis L . ) , trained as multiple leaders and irrigated by micro - sprinklers . The site was originally planted in 1962 with replants added in 1967 ; trees of both ages were used as long as tree conformation was similar . Soil type was a Tyndall very fine sandy loam . Trees were spaced at 9 ft between trees and 18 ft between rows , for 269 trees per acre . The experimental plot was laid out in two rows with a guard row between treated rows and at least one guard tree between treatment trees . The plot length was 369 ft and the width was 36 ft , for a total plot area of 0.3 acres . A single - factor design was used in which treatments were assigned at random ( by coin toss ) to one of two trees in 16 â?? pairs â?? of trees , each tree being a single - tree replicates with at least one untreated tree on each of the four sides of every replicate tree to minimize spray drift . Thus , replicates were grouped within rows . As the two levels of treatment ( no Messenger vs applied Messenger ) were assigned 1 to different subjects , treatment differences were tested statistically using two - sample t - tests . Grouping as a factor that may reduce experimental error was tested in analyses of variance ( ANOVAs ) . Both forms of statistical tests were performed with SigmaStat ( two - sample Studentâ??s t - Test and ANOVAs , P = 0.05 ; SPSS Inc , Chicago , IL ) . The Messenger treatment consisted of 9 ounces per 100 gallons per acre applied on five separate dates ( total of 36 ounces applied ) March 20 , 29 , April 9 , 23 and 30 . A fifth spray treatment was added after consultation with Mark Russell ( Eden BioSciences Corp . ) due to a predicted late maturation date following a cooler than normal spring . Sprays were applied with a a hand - held mist blower ( Stihl SR 400 , Andreas Stihl , Waiblingen , Germany ) . City well water ( non - chlorinated ) at pH 7.0 was used in the first application while orchard well water was used for the remaining applications ( pH 7.0 ) . The first Messenger spray was applied at â?? first white â?? or as the flowers were just beginning to open . Fruit were commercially hand - harvested on July 11 and July 23 , picking a minimum size ( 2.5 inches , 6.5 cm ) and larger on the first harvest , and stripping all fruit on the second harvest . A ten - fruit sample was taken at random from harvested fruit for each tree to evaluate fruit size . Total weight of fruit harvested was obtained for each harvest from each treatment replicate tree . Results and Discussion 1 A two - sample t - test ( also called an unpaired t - test ) compares results from two treatments applied to different experimental units while a paired t - test evaluates subjects that have each received both treatments at differing times . Messenger sprays did not increase weight per fruit in either harvest , although there was a 3 % increase in fruit size in the Messenger - treated fruit picked in the second harvest ( Table 1 ) . The per harvest or total yield of fruit per tree was not altered by Messenger treatment ( Table 1 ) . There was a non - statistically significant increase of 3 % in the weight of fruit harvested in the total yield in the Messenger - treated trees , although that may be due to an 8 % greater weight of fruit harvested in the first pick of the control fruit , thus allowing a longer growth period for the Messenger - treated fruit . Similarly , this is reflected in the 17 % greater yield ( by weight ) of the second harvest of Messenger - treated fruit . st + fall 1 ns harvest in ( 4.4 ) ( 3.4 ) petal % Fruit 43.1 51.2 days , ~ 14 ns + fall ( 4.2 ) ( 5.3 ) Total petal 64.2 62.2 fall , petal visible , harvest ns ( kg ) 28 ) . ( 4.2 ) ( 4.2 ) petals Yield and nd 37.7 31.2 2 white 15 ( July first harvests stages : ns harvest ( 3.3 ) ( 3.1 ) at postbloom significant . size 26.5 30.9 1st fruit and and non yields bloom = ns ns harvest at ( 4.6 ) ( 4.3 ) 2003 ; 0.05 ; 30 and 230.5 222.8 pear , nd = ( g ) 2 P 23 ( â?? SE ) ; fruit respectively . â?? Bartlett â?? 9 , April per t - Test Weight 25 , ns in x y 11 , ( 4.4 ) ( 3.8 ) harvest Studentâ??s days Messenger March 195.3 204.4 ~ 35 st 1 + by applied fall of separation Effects petal Messenger y Messenger Treatment days , Control 1 . Mean Table ~ 28 x y